Recall that in general,

`(a+b)^2=a^2+2ab+b^2`

We use this to expand out our given expression.

`(3 + sqrt(5))^2`

` = 3^2 + 2(3)(sqrt(5)) + (sqrt(5))^2`

`= 9 + 6sqrt(5) + 5`

`= 14 + 6sqrt(5)`